Biochar

ABSTRACT

The invention provides for methods, devices, and systems for pyrolyzing biomass. A pyrolysis unit can be used for the pyrolysis of biomass to form gas, liquid, and solid products. The biomass materials can be selected such that an enhanced biochar is formed after pyrolysis. The biomass can be pyrolyzed under specified conditions such that a selected biochar core is formed. The pyrolysis process can form a stable biochar core that is inert and/or resistant to degradation. The biochar or biochar core can be functionalized to form a functionalized biochar or functionalized biochar core. Functionalization can include post-pyrolysis treatments such as supplementation with microbes or physical transformations including annealing and/or activation.

CROSS-REFERENCE

This application is a continuation application of U.S. patentapplication Ser. No. 14/297,349, filed on Jun. 5, 2014, which is acontinuation application of U.S. patent application Ser. No. 13/748,164,filed Jan. 23, 2013, now issued as U.S. Pat. No. 8,747,797, which is acontinuation application of U.S. patent application Ser. No. 12/796,629,filed Jun. 8, 2010, now issued as U.S. Pat. No. 8,361,186, which claimsthe benefit of U.S. Provisional Application No. 61/185,141, filed Jun.8, 2009, each of which is entirely incorporated herein by reference.

BACKGROUND OF THE INVENTION

Increasing agricultural production in a sustainable way and mitigatingthe effects of climate change are two of the most important challengesfacing the modern world. These challenges include a need for higher cropyields, a need to make degraded soils more productive, and a need tomanage for productive agriculture with less dependable water resources.Some efforts have been made to reduce the long-term negative effects ofagriculture by crop-rotation and organic farming. Efforts have been madeto address climate change by reducing avoidable greenhouse gas emissionsthrough production of renewable energy and off-setting unavoidableemissions through sequestration of carbon in the environment. Somecarbon sequestration efforts have been aimed at storage of carbon insoil and of carbon dioxide in geologic formations. However, due to theinherent lack of long-term stability of plant derived biomass storage ofcarbon derived directly from plant biomass is not a long-term solution.Pyrolysis of biomass to produce a solid material called char, charcoalor more specifically biochar, which can be a product that is tailoredfor use as a soil amendment, can play a significant role in both ofthese efforts related to climate change and agriculture, but iscurrently limited by the use of biochars that exhibit instability ordegradation and which may have positive or negative effects on soilflora, fauna and/or plant growth. Therefore, there is a need forimproved methods, devices, and systems for the production of stableand/or beneficial biochars.

SUMMARY OF THE INVENTION

The invention provides for methods, devices, and systems for pyrolyzingbiomass and producing enhanced and/or functionalized biochar. Apyrolysis unit can be used for the pyrolysis of biomass to form gas,liquid, and solid products. The biomass can be pyrolyzed under specifiedconditions such that a selected biochar core, also referred to asbiocore elsewhere herein, is formed. The pyrolysis process can form astable biochar core that is inert and/or resistant to degradation.

One aspect of the invention provides for a method for producing aselected type of biochar core comprising the steps of introducing abiomass feedstock to a pyrolysis unit and pyrolyzing the biomass in thepyrolysis unit in accordance with a predetermined set of operatingparameters attuned to the selected biomass feedstock to produce theselected type of biochar core. The predetermined set of operatingparameters can include, pre or post pyrolysis treatments of biochar aswell as an established temperature range and rate of temperature changethat corresponds to the selected type of biochar core. The inventionalso provides for systems and methods that include pre and/or postpyrolysis treatments of biochars.

Another aspect of the invention provides for the production of enhancedand/or functionalized biochar. Enhanced biochar can be produced byblending, mixing, other otherwise combining selected feed materials suchthat a selected biochar is formed by pyrolysis. Functionalized biocharcan include, for example, a biocore that has been supplemented with amicrobe or a nutrient or an organic substance.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 shows a diagram of a process for producing an enhanced biochar.

FIG. 2 shows a diagram of a process for producing a functionalizedbiochar.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides for methods, devices, and systems for pyrolyzingbiomass. A pyrolysis unit can be used for the pyrolysis of biomass toform gas, liquid, and solid products. The gas, liquid, and solidproducts can be syngas (the non-condensable, permanent gases includingCO, CO₂, CH₄, H₂ and higher hydrocarbons of formula C_(x)H_(y) which canbe gaseous at 20° C. and atmospheric pressure), bio-oil (also referredto as pyrolysis liquids, pyroligneous acid, bio-fuel-oil, pyrolysistars), and char, charcoal, biocarbon, agrichar, biochar, enhancedbiochar, or biocore (also referred to as biochar core elsewhere herein),respectively.

As shown in FIG. 1, selected biomass materials, can be pyrolyzed atspecified pyrolysis conditions to form selected enhanced biochars. Theselection of biomass materials and/or the specified pyrolysis conditionscan be altered to produce a variety of enhanced biochars that can betailored to a variety of applications, described herein.

As shown in FIG. 2, selected biomass materials can be pyrolyzed underspecified conditions such that one or more selected biocores are formed.The pyrolysis process can form one or more stable biocores that areinert and/or resistant to degradation. The biocores can be configured,for example by blending with a supplement, for use as a soil amendment,as a potting mix, as a substitute in a growing media (including peatand/or compost media), as a horticultural media, as a carbonsequestration agent, a mitigant for soil greenhouse gas emissions, afertilizing agent, a landscaping amendment, a turfgrass establishment, abioremediation agent, a delivery agent for fungi or bacterialpopulations, or any combination thereof and not limited to thesupplements listed. The biochar cores can be further tailored, enhancedand/or functionalized using a variety of methods, systems and processesdescribed herein. In some embodiments of the invention, the biocores canbe tailored, enhanced, and/or functionalized to a particular end use orapplication.

I. Biomass

The biomass used for formation of pyrolysis products can be obtainedfrom a variety of sources. The biomass can be any material containingorganic carbon. For example, the biomass can be plant material,cellulosic materials, lignin containing material, animal by-products,organic wastes, landfill matter, marine waste, agricultural waste,animal or human waste, other naturally derived sources of carbon, or anycombination thereof. The biomass materials can also include compost,sewage sludge, or vinasse. Biomass materials can be blended to form abiomass feedstock. For example, biomass obtained from a softwood (e.g.,a pine tree) or a hardwood (e.g., and oak tree) can be blended withpoultry litter and then pyrolyzed. In some embodiments, metals or otherchemicals can be blended with the biomass prior to pyrolysis. Examplesof the pyrolysis of poultry litter and animal waste are described inJP2001252558, U.S. Pat. No. 6,189,463 and U.S. Patent Publication No.2009/0031616, each of which are incorporated herein by reference in itsentirety.

In some embodiments of the invention, the biomass is selected based onthe chemical content of the material, the elemental composition of thebiomass, or the content of its elemental composition. For example, abiomass can be selected on its content of carbon, hydrogen, oxygen,nitrogen, phosphorous, potassium, selenium, cobalt, iron, manganese orany combination thereof in the biomass and any other elements. Thebiomass can be selected based on the content of water, oil,hydrocarbons, volatile compounds, organic carbon, volatile organiccarbons, or any combination thereof. Any of these content parameters canbe selected to be higher, lower, or up to about 1, 5, 10, 15, 20, 25,30, 40, 50, 60, 70, 80, 85, 90, 95, or 99% by weight or volume.

In some embodiments of the invention, the biomass feedstock can beselected based on the energy content of the biomass materials. Theenergy content of the biomass feedstock, determined by the biomassmaterials used, can be at least, up to, greater than, or less than about1, 5, 10, 15, 20, 25, or 30 GJ/ton, which can be measured on a dry (suchas atmospheric or oven dry) weight or dry ash-free basis. In someembodiments of the invention, the biomass feedstock can be elected basedon the particle size and shape of the biomass materials. The particlesize and shape of the biomass feedstock can be controlled by cutting,crushing, grinding, screening or breaking of a biomass material. Forexample, trees can be chipped and/or ground to a particular particlesize and then fed to a pyrolysis unit.

Selection of the biomass feedstock can allow for the formation ofpredetermined pyrolysis products. For example, a biomass feedstock canbe formed from a crop such as switchgrass or miscanthus or a cropby-product such as corn stover and a biomass material with high nutrientcontent, such as manure or rapemeal, to form biochar that may be used asa nutrient source. As another example, wood or high ash feedstocks(including feedstocks having greater than about 5% ash) can besupplemented to a biomass material to enhance the production of liquidpyrolysis products.

Pretreatment of biomass can relate to physical preparation of thebiomass and may include drying (air, steam, warm exhaust gases orother), size reduction (milling, grinding, chopping, shredding), and/orscreening to a certain size fraction or range of size fractions. Biomasscan also be pretreated by the addition of elements and/or compounds,reacted with chemicals to reduce or remove any of the biomassconstituents (including acid washing, alkali treatment, hot waterwashing, cold water washing, steam exposure, washing with an organicsolvent, and/or dissolution in ionic liquids). Biomass can also bethermally treated after drying to reduce its degree of polymerization,remove volatile compounds and/or extractives. This process can sometimesbe called conditioning or torrefaction. In some embodiments of theinvention, conditioning or torrefaction can be performed at temperatureslower than typical pyrolysis temperatures.

The biomass materials can be selected such that the pyrolysis productsinclude an enhanced biochar or enhanced biochar core. The enhancedbiochar or biochar core can be used for a variety of applications,including any application described herein. The enhanced biochar orbiochar core can also be functionalized to form a functionalized and/orenhanced biochar core.

II. Pyrolysis

The invention provides for a pyrolysis unit that can be used forformation of pyrolysis products from a biomass feedstock. The pyrolysisunit can control the pyrolysis conditions of the biomass feedstock suchthat selected types of pyrolysis products are formed. In someembodiments of the invention, a selected type of biochar core is formedfrom a selected biomass feedstock. The biochar core can be a stablebiochar core that is inert and/or resistant to degradation, for examplemicrobial, biological, chemical, thermal and/or oxidative degradation.The pyrolysis unit can be a gasifier or reactor, as described in U.S.Pat. Nos. 6,830,597 and 6,902,711, each of which are incorporated hereinby reference in their entirety. Solid pyrolysis products, includingbiochar, that can be formed using the methods and devices describedherein can also be referred to as pyrolysis char, charcoal, bio-carbon,or other similar names.

The pyrolysis unit can be operated in a batch, continuous, orsemi-continuous mode. A biomass feedstock can be supplied or introducedto the pyrolysis unit, the biomass feedstock can be heated and/orpyrolyzed in the closed pyrolysis unit to form pyrolysis products, andthen the pyrolysis unit can be opened for the removal of the pyrolysisproducts. The biomass feedstock can also be left in the pyrolysis unituntil it has been partially or fully pyrolyzed and cooled down, withremoval of gas and vapor during pyrolysis; retention of all productsinside the reactor until it has cooled down, or partial removal of thegas and vapor products during the pyrolysis process.

The pyrolysis products can be a selected type of biochar core that areproduced from a predetermined biomass feedstock using a predeterminedset of pyrolysis conditions and, optionally, secondary and/or tertiarytreatment of the resultant biochar. For example, Feedstock A that ispyrolyzed under conditions G produce biochar core X. Feedstock A can beformed from a variety of biomass materials, so long as the biomassmaterials produce a blend of materials that exhibit properties that arewithin a specified range for feedstock A. Based on the properties of thefeedstock, the conditions G are selected such that biochar core X willbe formed. For example, pyrolysis time or temperature can be increasedif the water content of the feedstock is increased. Conversely,pyrolysis time or temperature can be decreased if the water content ofthe feedstock is decreased. Alteration of the pyrolysis conditions basedon the feedstock can allow for the production of biochar core X, whichexhibits selected properties. Under certain circumstances, a feedstockcan be chosen that does not fall within the specified range ofproperties for feedstock A. In this case, a biochar core that is notbiochar core X may be formed.

The pyrolysis of a biomass material involves a wide range of parameters,relating to the feedstock and to the pyrolysis process, including thefollowing parameters:

Biomass Related Parameters Include:

-   -   intrinsic properties of the biomass (e.g., original lignin,        cellulose, hemi-cellulose, ash content and composition and        extractives);    -   biomass pretreatment (e.g., additives/ash content and        concentration, moisture, chemical composition, changes in the        proportions of lignin, cellulose, hemi-cellulose and        extractives);    -   biomass degree of polymerisation;    -   biomass density;    -   biomass particle size;    -   biomass particle shape; and    -   biomass physical and thermal properties (e.g., specific heat        capacity, thermal conductivity, permeability).

Pyrolysis Reactor Operation Parameters Include:

-   -   reactor temperature;    -   temperature at which pyrolysis occurs at the surface of the        particle and/or at the geometric centre of the particle to        assess completeness of pyrolysis;    -   product reactor residence time in the reactor;    -   product temperature in the reactor;    -   biomass heating rate and heat transfer;    -   biomass decomposition temperature or temperature range;    -   pressure (e.g., hydrostatic and mechanical); and    -   gaseous environment (e.g., gaseous environment in the reactor).

Parameters Relating to Recovery of the Final Products Include:

-   -   rate of thermal quenching of the products (e.g., char can be        cooled with gas, liquid or solid) and    -   time/temperature profile of the cooling of the biochar.

One or more of these parameters, or any other parameters or conditionsdescribed herein, can be controlled to produce the biochar core productsdescribed herein. These parameters can be controlled to variable degreesand some parameters may have a greater influence on the properties ofthe pyrolysis products than others.

In some embodiments of the invention, materials can be fed to or removedfrom the pyrolysis unit under controlled conditions while the pyrolysisunit is operating. For example, syngas, bio-oil, biochar core, or anycombination thereof produced during pyrolysis can be collected from thepyrolysis unit and used for heating of the pyrolysis unit, heat export,power generation or other applications including but not limited to thesynthesis of chemicals and derived products. Alternatively, a biomassfeedstock with or without reagents can be added to the pyrolysis unitduring the pyrolysis process. The pyrolysis unit can have a plurality ofstages. The pyrolysis unit can have a first stage for heating and/orpyrolyzing the biomass feedstock under a first set of conditions and asecond stage for heating and/or pyrolyzing the biomass feedstock under asecond set of conditions. The biomass feedstock can be transferred firstto the first stage and then to the second stage. Alternatively, thebiomass feedstock can be moved through the pyrolysis unit in acontinuous mode. The biomass feedstock can be pyrolyzed under aplurality of conditions as the biomass feedstock moves through thepyrolysis unit, or conversely retained in the unit until the processinghas been completed.

The pyrolysis unit can have one or more temperature sensors formonitoring and controlling the temperature of the biomass feedstockduring pyrolysis. The temperature sensors can be positioned throughoutthe pyrolysis unit such that the temperature sensors provide effectivemonitoring of the temperature of the biomass feedstock, the surfacetemperature of the biomass feedstock, and/or the environment surroundingthe biomass and/or reagents. Similarly, the pyrolysis unit can have oneor more pressure and/or oxygen sensors for monitoring and controllingthe amount of pressure and/or oxygen in the pyrolysis unit. The pressureand/or oxygen sensors can be spaced throughout the pyrolysis unit forappropriate monitoring of the pressure and/or oxygen levels in thepyrolysis unit. Other instrumentation can be added as required tomonitor and control the process.

Heat can be supplied to the pyrolysis unit using a variety of energysources and in a variety of ways (hot gases, molten salts, hot sand,contact with heated metal surfaces, or microwaves). For example, energysources can be combusted for the formation of heat, which can betransferred to the pyrolysis unit. Alternatively, microwave energy canbe utilized for the pyrolysis of the biomass feedstock, as described inPCT Publication No. WO2008/079029, incorporated herein by reference inits entirety.

The pyrolysis unit can be operated under predetermined reactionconditions such that one or more selected pyrolysis products are formed.For example, the pyrolysis unit can be controlled such that a biomassfeedstock is heated at a specific rate to a desired temperature whilebeing exposed to a specified level of oxygen. The specific rate can beup to about, about, or less than about 0.01, 1, 10, 100, or 1000° C. persecond, which can be determined at the reaction interface. The specificrate can be controlled to within about or less than about 5, 10, 20, or40° C. per second, which can be determined at the reaction interface orat the center of the particle. The temperature of the biomass feedstock,which can be the final or peak temperature, can be controlled to withinabout or less than about 100, 20, 10, or 5° C. The final temperature ofthe pyrolyzed biomass can be a temperature up to about 200, 500, or1000° C. The pyrolysis unit can be controlled such that the biomassfeedstock is held at a specific temperature for a desired amount oftime. The time can be controlled to within about or less than about 50,5, or 0.5 minutes. The pyrolysis products can be formed within thepyrolysis unit in about, greater than about or less than about 0.001,0.01, 0.1, 1, 2, 3, 4, 5, 6, 7, or 10 days.

Some conditions for performing pyrolysis are described in PCT PatentPublication No. WO2009/016381, incorporated herein by reference in itsentirety. The pyrolysis or charring process can involve heating abiomass feedstock over 250° C. under oxygen deficient conditions leadingto its decomposition. Thus, the absence of an oxidizing agent, such asan acid, steam or air, may be preferred. The temperature will normallybe selected according to the substance to be charred and the extent towhich it is desired to remove unwanted compounds (organic or inorganic)or other contaminants. The process may not need to be sealed, as theheated material can give off volatile products (condensable andnon-condensable). Air ingress to the pyrolysis unit can be minimized orobviated by the addition of inert gas purging (N₂, Ar (or other noblegas), combustion products (CO₂, CO, H₂O), steam or restricting theingress of air by operating the unit under a positive pressure). In someembodiments of the invention, pyrolysis conditions can maximizeproduction of energy in the form of a variety of products, such assyngas or biooil™, can maximize the production of a selected type ofbiochar, or can be optimized for a balance between energy production andbiochar production. The selected type of biochar core can haveparticular characteristics, as described herein.

Some pyrolysis processes can be classified as slow pyrolysis or fastpyrolysis. Slow pyrolysis can be performed at temperatures of between300 and 450° C. Slow pyrolysis can involve heating biomass feedstock ata temperature rate between about 0.1 to 50° C. per second. Fastpyrolysis can be performed at higher temperatures, which can be from400-1000° C., depending on whether liquids or gases are to be optimizedand/or the nature of the feedstock. Fast pyrolysis can involve heatingbiomass feedstock at a temperature rate change, which can be determinedat the reaction interface, between about 100 to 1000° C. per second. Theyield of products from pyrolysis, and/or whether or not the pyrolysis isfast or slow, can vary with temperature, feedstock composition,feedstock size or feedstock shape, residence time and heating rate. Insome embodiments of the invention, increased amounts of char can becreated per unit biomass at the lower pyrolysis temperatures. Hightemperature pyrolysis can produce greater amounts of syngas from thebiomass.

Fast pyrolysis, including fast pyrolysis of soft or hardwood particlesless than 6 mm in their maximum dimension at a reactor temperature of450-525° C., can yield about 75% bio-oil (which may include reactionwater), 14% biochar, and 11% syngas, and decomposition of the feedstockcan be completed in seconds. Slow pyrolysis can be optimized to producesubstantially more biochar (which can be up to ˜45-50 wt % of the dryash free biomass) and can take on the order of hours to complete. Insome embodiments, slow pyrolysis can be performed at high pressure.

The invention provides for methods for producing a biochar core that canhave particular carbon and/or volatile carbon content. Biocharexhibiting these particular properties can be produced using selectedpyrolysis conditions described herein. For example, a biomass feedstockis heated at a sufficiently slow rate and for a sufficient amount oftime such that volatile organics are allowed to escape from the biomassand do not recondense within the pyrolysis reactor. The volatileorganics can be removed from the pyrolysis reactor thereby preventingthe volatile organics from recondensing in the pyrolysis reactor or onthe pyrolyzing biomass. Alternatively, the reaction conditions can besuch that the volatile organics do not recondense in the pyrolysisreactor. In other embodiments of the invention, the reaction conditionscan be such that the volatile organics recondense in the pyrolysisreactor, and in some cases, on the biomass feedstock. The rate ofheating or the amount of heat applied can be such that the rate ofrelease of volatile organics is less than about, about, or greater thanabout 75, 50, 30, 20, 10, 5, or 1% per hour of the total volatileorganics present in the feedstock or that can be released by pyrolysis.The rate of heating or amount of heat applied can have multiple stages.For example, the rate of heating or amount of heat applied can be highand then low, or low and then high. In some embodiments of theinvention, the rate of heating or amount of heat applied can change on alogarithmic, exponential, or linear scale. Examples of the range ofpossible values of pyrolysis conditions and properties of resultantchars, including amount of volatile products in chars, are given inTable 1.

TABLE 1 Properties of charcoal produced at various temperatures fromAcacia bussei produced in a muffle furnace Pyrolysis Fixed GrossCalorific Charcoal Energy temp C H O^(a) Ash Water volatiles Carbonvalue yield^(b) yield^(c) [° C.] [wt %] [wt %] [wt %] [wt %] [wt %] [wt%] [wt %] [MJ/kg] [wt %] [%] 300 30.2 5.67 63.73 0.4 1.9 70.8 28.8 22.456.27 65.92 400 71.5 3.93 22.17 2.4 2.8 30.9 66.7 29.88 28.03 43.80 50087.0 3.10 8.50 1.4 2.8 17.7 80.9 32.14 22.65 38.07 600 87.5 2.67 6.932.9 1.0 7.1 90.0 33.20 21.63 37.56 700 92.4 1.71 3.89 2.0 1.8 3.9 94.133.40 20.16 34.22 800 93.4 1.03 3.57 2.0 2.2 2.4 95.6 33.90 19.54 34.64Notes: ^(a)assumes no sulphur or nitrogen present ^(b)dry weight ofcharcoal divided by weight of wood ^(c)gross calorific value of charcoalmultiplied by charcoal yield divided by gross calorific value of thewood.

Reference: Hollingdale, A. C., Krishnan, R., Robinson, A. P., “CharcoalProduction A Handbook”, Chapter 2, page 7, Eco-logic books, 1999, ISBN 1899233 05 9 (which is incorporated herein by reference in its entirety).

The biomass feedstock can be heated for enough time and under sufficienttemperature conditions that the biochar core product has a selectedand/or controlled carbon content. The carbon content can be greater thanabout, about, or less than about 10, 20, 40, 60, 75, 80, 90, 95, 97, 99,or 99.5 wt %. The carbon content can be measured as a portion of the dryweight of the biochar.

The biomass feedstock can be heated for enough time and under sufficienttemperature conditions that the biochar core product has a selectedand/or controlled volatiles content. The volatiles content can begreater than about, about, or less than 90, 80, 50, 30, 25, 20, 15, 10,5, 1, or 0.1 wt %. The volatiles content can be measured as a portion ofthe dry weight of the biochar or the total weight of the biochar.

In some embodiments of the invention, the pyrolysis conditions can besuch that a selected biochar core has an elemental composition orphysical characteristics as described herein. For example, the pyrolysisconditions can be such that biochar core has a selected content ofcarbon, nitrogen, oxygen, hydrogen, potassium, or phosphorous.Alternatively, the pyrolysis conditions can be such that the biocharcore has a desired cation exchange capacity, density, porosity, poresize, average pore size, crystallinity, size distribution, surface area,surface area per mass, or adsorption capacity.

In some embodiments of the invention, the conditions for pyrolysis caninclude a temperature heating rate that is less than about 50, 10, 5, 1,or 0.1° C. and a final temperature can of greater than about 500, 600,700, 800, 900, or 1000° C.

In some embodiments of the invention, completion of the pyrolysisprocess is determined by monitoring the rate of release of compoundsfrom the biomass feedstock. Once the rate of release of compounds hasdecreased to about 0.5, 1, 5, 10, 20, or 50% of the maximum rate ofrelease of compounds, the pyrolysis process may be deemed to havecompleted. The compounds that are monitored for release can bevolatiles, organic carbons, volatile organic carbons, volatile carbons,water vapor or organic volatiles and/or permanent gases such as CO₂, CO,H₂, CH₄ and other higher hydrocarbons. Alternatively, the pyrolysisprocess can be performed until the biochar product formed has a volatile(volatile containing solid compounds, volatile organic compounds, orvolatile carbon compounds) content of greater than about, about, or lessthan about 90, 80, 50, 30, 25, 20, 15, 10, 5, 1, or 0.1 wt %. Thepyrolysis conditions can be such that the amount of volatiles in thebiochar product can be controlled to within 0.1, 1, 5, or 10 wt %. Theamount of volatiles can be measured by analysis of the composition ofthe biochar immediately after removal from the pyrolysis reactor orafter post-pyrolysis treatment. In some embodiments, the percentage isdetermined as a percentage of total mass of the biochar. In otherembodiments of the invention, the percentage is determined as apercentage of non-volatile carbons.

The invention provides for use of the pyrolysis products for thepyrolysis process. For example, the invention provides for post-heatingmanagement of the pyrolysis products. Heat in the pyrolysis products canbe recovered and/or used for the heating and/or drying and/ortorrefaction of the biomass feedstock. Alternatively, the heat from thepyrolysis products can be used for the generation of energy. Forexample, heat from the pyrolysis products can be used to heat a steamgenerator for production of electricity or for activation of the biocharusing steam, CO₂, or combination of thereof. In other embodiments of theinvention, pyrolysis products can be used for the generation of energy,which can be used to power the pyrolysis process. The invention alsoprovides for a variety of methods and processes to modify the pyrolysisproducts, described herein.

III. Biochar Post-Pyrolysis Treatment

In some embodiments of the invention, the pyrolyzed biomass is subjectedto post-treatment. Post-treatment can be used to control thecharacteristics of the biochar core product, such that a specificbiochar core product is formed. Post-treatment can include solventwashing, high temperature heating, gasification, sorting, grinding,chipping, or chopping. For example, pyrolyzed biomass can be subjectedto an organic solvent wash to remove volatiles from the pyrolyzedbiomass. Alternatively, the pyrolyzed biomass can be sorted for sizeand/or density, such that pyrolyzed biomass particles of a specifiedsize and/or density distribution are grouped together.

IV. Biochar Core

The biochar core produced using the methods, devices, and systemsdescribed herein can have selected properties that improve thefunctional characteristics of the biochar core in a variety ofapplications. These properties can include the elemental composition ofthe biochar core, such as carbon, total carbon, organic carbon, totalorganic carbon, nitrogen, oxygen, hydrogen, potassium, or phosphorouscontent and other non-specified elements. The selected content levels ofthese elemental compositions within the biochar core can be any leveldescribed herein. Other selected properties of the biochar core caninclude cation exchange capacity, density, porosity, pore size, averagepore size, crystallinity, size distribution, surface area, surface areaper mass, or adsorption capacity. The porosity can be a fraction of thetotal volume greater than about, about, or less than about 0, 0.1, 0.2,0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0. The pore size or average poresize can be in the range of 5 to 50 μm. The pore size or average poresize can be greater than about, about, or less than about 0.01, 0.1, 1,5, 10, 25, 50, 100, 200, 400, or 1000 μm. The surface area can begreater than about, about, or less than about 1, 5, 50, 100, 300, 500,750, 1000, 2500, or 5000 m² per gram.

The biochar core properties can be selected such that the biochar coreis stable, inert and/or exhibits reduced degradation over time. Thedegradation of the biochar core can be through biotic, abiotic, chemicalor oxidative reactions. The degradation can be measured by determiningthe amount of carbon in the biochar core as a percent of initial carbonin the biochar core after pyrolysis. The carbon can be organic carbon,inorganic carbon, or both inorganic and organic carbon. The rate ofdegradation can be about or less than about 20, 15, 10, 5, 2.5, 1, 0.5,or 0.1% per year. The rate of degradation can be measured over a timespan of 1, 2, 5, or 10 years or longer. Alternatively, the rate ofdegradation can be measured over one, two, or three months in the first,second, third, fourth, or fifth year after production of the biocharcore or after use of the biochar core for a particular purpose. Theparticular purpose can be use of the biochar core as a soil amendment,fertilizing agent, microbial delivery agent, or any other purposedescribed herein.

The rate of degradation can be controlled by selection of the propertiesof the biochar core. For example, the biochar core produced using themethods described herein can have a low volatile organic carbon contentand/or a highly stable non-volatile component. This can reduce thedegree that the biochar core can be degraded by microbial organisms thatmay utilize the biochar core as an energy or nutrient source. In someembodiments of the invention, the biochar core can have a controlledrate of degradation based on the form of carbon in the biochar core.These forms can include any of the forms described herein, and can beselected by a variety of parameters, including the type of biomass feedmaterial. In other embodiments of the invention, post-pyrolysistreatments, such as annealing, can be used to control the rate ofdegradation of the biochar core. The biochar core can be produced suchthat it has a high carbon content and can easily degrade or be stable.

V. Biochar Functionalization

The biochar core and/or enhanced biochar core can be functionalized orprocessed by a variety of methods to form a functionalized biochar. Forexample, the biochar core can be sorted, chemically or physicallytreated, or supplemented with nutrients, chemicals, or organisms. Insome embodiments of the invention, the biochar core can be sorted bysize or density such that biochar core particles of a particular size,distribution or density are grouped together. Alternatively, the biocharcore can be treated chemically and/or physically to form biochar withactivated carbon. The activated carbon can have an increased surfacearea, porosity, water retention, or cation exchange capacity that allowsfor improved functional activity of the biochar core. For example, thebiochar with activated carbon can have increased capacity to holdnutrients or microbial inoculants.

In some embodiments of the invention, the biochar core or activatedbiochar core are mixed or blended with a supplement. The supplement caninclude inorganic chemicals such as fertilizers and nutrients.Alternatively, the supplement can include organic materials withproperties that increase the CEC, nutrient content or performance ofbiochar as a microbial habitat or it may be organisms such as fungi orbacteria or combinations of thereof

The chemicals that can be mixed with the biochar core include nitrogen,phosphorous, potassium, calcium, sulphur, and magnesium sources. Thesources can be in the form of fertilizer, compost, manure, ammonia,ammonium nitrate, urea, lime, limestone, rock phosphate, salt peter,gypsum, crop or other inorganic and organic compound containing theseelements.

The biochar products can be supplemented with nutrient sources or othermaterials, such as those described herein, to form a biochar productwith a known, desired, or selected amount of nutrients or othermaterials.

Organisms that can be supplemented to the biochar core can include fungiand bacteria. In some embodiments of the invention, the biochar core canbe supplemented with trichoderma. Examples of trichoderma are discussedin U.S. Pat. No. 6,060,507, incorporated herein by reference in itsentirety.

Other organisms can include Accumulibacter phophatis, Anabaena, Azolla,Bacillus circulans, Bacillus subtilis var natto, Bifidobacteriumanimalis, Bifidobacterium bifidum, Bifidobacterium longum, Deinococcusradiodurans, Lactobacillus acidophilus, Lactobacillus buchneri,Lactobacillus bulgaricus, Lactobacillus casei, Lactobacillusdelbrueckii, Lactobacillus plantarum, Lactococcus diacetylactis,Lactococcus lactis, Mycorrhiza, Pseudomonas aeruginosa, Pseudomonasputida, Ralstonia metallidurans, Rhizobia, Rhodobacter, Rhodopseudomonaspalustris, Rhodopseudomonas sphaeroides, Saccharomyces cerevisiae,Streptococcus thermophilus, Ulocladium oudemansii, or Xanthomonasmaltophilia. The rhizobacteria can be a rhizobium plant growth promotingrhizobacteria. Combinations of these organisms can be supplemented to abiochar core. A combination of organisms can be chosen based on thesymbiotic relationships between organisms and the desired functionalityof the biochar core. For example, thiobacteria can be supplemented to abiochar core for forming a bioremediation agent.

Organisms that can be supplemented to the biochar core can be organismsthat have been identified as an efficient microorganism. These organismscan control the growth of fungus or other adverse species.Alternatively, these organisms can be used for the generation ofnutrients that are beneficial to the growth of particular organisms,such as plants. For example, some organisms can be used to increase therate of nitrogen fixation in soil.

The organisms can be added to the biochar core along with nutrients thatmay allow the organisms to remain viable until the biochar is applied toa particular site. In other embodiments of the invention, organisms canbe added to the biochar core without nutrients or selected nutrients orwith or without organic supplements. The functionalized biochar can bedesigned such that a sufficient amount of colony-forming units of anorganism are present upon application of the functionalized biochar to asite for inoculation by the organism.

VI. Biochar Applications

The methods of the invention provide for the use of biochar for avariety of purposes. The biochar can be used as a soil amendment,potting mix, a substitute in a growing media (including peat and/orcompost media), a horticultural media, a carbon sequestration agent, afertilizing agent, a turfgrass establishment, a bioremediation agent, adelivery agent for a fungi or bacterial population, a synthetic “terrapreta” (or equivalent material) or any combination thereof.

In some embodiments of the invention, the biochar is used for carbonsequestration by fixing of carbon in the soil in a recalcitrant form. Anexample of the use of biochar for carbon sequestration is described inU.S. Patent Application No. 2004/0111968, incorporated herein byreference in its entirety. When the biochar is used for carbonsequestration, the biochar core is selected to have resistance todegradation, as described herein. The time scale for the biochar corecan be greater than about, less than about, or on the order of hundredsof years.

In other embodiments of the invention, biochar or an enhanced and/orfunctionalized biochar can be used for mitigation of soil greenhouse gasemissions. For example, an enhanced and/or functionalized biochar can beused to reduce emission of methane or nitrogen containing gases, such asnitrous oxide.

In other embodiments of the invention, the biochar is used for on-demandrelease of chemicals or other materials. These chemicals can befertilizers, nutrients, or other materials that are depleted over timeat a particular site. The chemicals can also be chemicals that create aprotective environment for a desired organism to be grown, e.g.,pesticides or insecticides or other chemicals that may attract orsupport beneficial organisms. The fertilizers, nutrients, or othermaterials can be depleted by organisms such as plants and microbes. Thechemicals can be released from the biochar based on the concentration ofthe fertilizer, nutrients, or other materials in the surroundingenvironment. The release of the chemicals can be such that theconcentration of the chemical in the surrounding environment ismaintained at a relatively constant level.

The biochars described herein can be used to enhance agriculturaloutput, horticultural qualities, or turf grass. For example, biocharscan be used to improve the yield of an agricultural crop and/or toimprove the resistance of the crop to detrimental environmental effects.Detrimental environmental effects can include harmful organisms, e.g.,harmful fungi or insects, diseases, drought, low water, heat, wind,cold, frost, pollution, saline-containing water, and polluted water. Insome embodiments of the invention, the biochars described herein canimprove water retention, drainage, aeration, or the effects ofcompaction. In other embodiments of the invention, the biochars can beused to improve crop quality or nutritional value. Blends of organism,nutrient, and biochar can be used to form “terra preta” soil. Adiscussion of terra preta can be found in PCT Publication No. WO2009/021528 and U.S. Patent Publication Nos. 2004/0111968 and2007/0148754, each of which are incorporated herein by reference in itsentirety.

The biochars described herein can lead to increased crop yield, loweruse of water or irrigation, less nutrient run-off, reduced fertilizeruse and cost, reversed soil degradation, and elimination, reduction, oravoidance of GHG emission from soil.

The biochars that can be produced using the methods and systemsdescribed herein can be used to reduce pollution in water run-offstreams and also to improve retention of water. The biochars can be usedto remove phosphorous and nitrogen compounds from water streams or fromother sources. The biochars can be used to protect ground water andother water bodies from undesired effects. For example, biochar can bedistributed at an agricultural site or a farming location such thatrunoff or other undesired materials do not contaminate the ground wateror other bodies of water.

In some embodiments of the invention, biochar is produced that can beused for bioremediation. The biochar can be designed to absorb toxicchemicals or have organisms that can convert the toxic chemicals to lessharmful chemicals. Examples of using biochar for bioremediation arediscussed in PCT Publication No. WO 2009/016381, incorporated herein byreference in its entirety.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A biochar that is usable for growth of anorganism in soil, comprising a biochar core comprising (i) a porositythat is less than or equal to about 0.9 of a total volume of saidbiochar core, (ii) a surface area greater than or equal to about 1 m²per gram or less than or equal to about 5000 m² per gram, and (iii)pores with average pore sizes less than or equal to about 400micrometers, wherein said biochar core has increased capacity to hold anutrient or biological energy source relative to a biomass precursor ofsaid biochar core.
 2. The biochar of claim 1, wherein said biochar corecomprises pores with average pore sizes less than or equal to about 200micrometers.
 3. The biochar of claim 2, wherein said biochar corecomprises pores with average pore sizes from about 5 micrometers to 50micrometers.
 4. The biochar of claim 1, wherein said porosity is lessthan or equal to about 0.7.
 5. The biochar of claim 2, wherein saidbiochar core includes a supplement that includes said nutrient orbiological energy source, which supplement promotes growth of saidorganism in said soil.
 6. The biochar of claim 5, wherein saidsupplement includes one or more microbes, a nutrient or energy source, afertilizer, or any combination thereof.
 7. The biochar of claim 6,wherein said one or more microbes are selected from the group consistingof rhizobacteria, a trichoderma and a mycorrhiza.
 8. The biochar ofclaim 5, wherein said supplement includes one or more nutrients selectedfrom the group consisting of nitrogen, phosphorus, potassium, selenium,cobalt, iron, calcium, magnesium and manganese.
 9. The biochar of claim1, wherein said surface area is greater than or equal to about 1 m² pergram.
 10. The biochar of claim 9, wherein said surface area is greaterthan or equal to about 50 m² per gram.
 11. The biochar of claim 1,wherein said surface area is less than or equal to about 5000 m² pergram.
 12. The biochar of claim 11, wherein said surface area is lessthan or equal to about 500 m² per gram.
 13. The biochar of claim 1,wherein said biochar core comprises less than about 30 wt % volatilecompounds.
 14. The biochar of claim 1, wherein said biochar corecomprises less than about 30 wt % oil.
 15. A method for producing abiochar that is usable for growth of an organism in soil, comprisinggenerating a biochar core comprising (i) a porosity that is less than orequal to about 0.9 of a total volume of said biochar core, (ii) asurface area greater than or equal to about 1 m² per gram or less thanor equal to about 5000 m² per gram, and (iii) pores with average poresizes less than or equal to about 400 micrometers, wherein said biocharcore has increased capacity to hold a nutrient or biological energysource relative to a biomass precursor of said biochar core.
 16. Themethod of claim 15, further comprising generating said biochar core bypyrolyzing said biomass under operating parameters attuned to saidbiomass.
 17. The method of claim 16, wherein said operating parametersinclude a time-dependent temperature profile that corresponds to saidbiochar core.
 18. The method of claim 16, wherein said operatingparameters include an established temperature range and rate oftemperature change that corresponds to said biochar core.
 19. The methodof claim 15, further comprising blending said biochar core with organicmatter, washing said biochar core, annealing said biochar core, oractivating said biochar core.
 20. The method of claim 15, furthercomprising heating said biomass supplemented with a feedstock having anash content greater than about 5%.
 21. The method of claim 15, furthercomprising heating said biomass under oxygen deficient conditions togenerate said biochar core.
 22. The method of claim 15, furthercomprising contacting said biochar core with a supplement that includessaid nutrient or biological energy source to functionalize said biochar,which supplement promotes growth of said organism in said soil.